The proper use of ailerons when taking off in a crosswind is to use them to give the airplane a very slight roll into the wind. The idea is based on the effect that is used by airplanes designed with dihedral like our rudder/elevator gliders. The idea is often described as keeping the upwind wing from presenting it's underside to the gusts. In fact, it's mainly to keep the AOA of the upwind wing from creating unwanted lift from the gusts. The recommendation is to hold a bit of aileron into the wind. It's a suggestion to hold a steady amount of "trim" that's easily and quickly removed without having to do anything more than slightly moving your stick.

It does not contradict the idea that sudden attempts to steer an airplane in the midst of taking off increases the possibility that excessive aileron deflection of a wing already close to the stall would be stalled by that deflection.

The reason it's suggested to NOT try to steer your airplane off the runway with ailerons, to use the rudder, is because of the rudder doesn't increase the probability of a wing stall as quickly or easily as increased aileron deflection does. It's safer to steer your airplane on takeoff with the rudder. From the start of the takeoff roll until the model is safely airborne.

If you're a beginner who wants to succeed at your new hobby, it's really a good idea for you to learn to steer your airplane on takeoff with your rudder instead of the ailerons.